I was honoured to speak with the chief engineer of the new Toyota Prius, Akihiko Otsuka, at the Geneva Motor Show recently. Honoured, because the young dude is quite a guy.

Oozing enthusiasm for the Prius, his groundedness and sheer enthusiasm wowed me. We’re close in age, he and I, and I really felt how ‘here and now’ he is. Think everything that’s dynamic and invigorating about modern Japan, for an idea of his approach.

This whirlwind of ideas shows in the new car, which really is quite something. Official fuel economy of the current one doesn’t always carry through to reality, I said. Unbowed, he admitted so – a key target of the new car was to improve on this.

He told his team to benchmark against the Volkswagen Golf 1.9 TDI – not the default 2.0 TDI, which is a fair bit less efficient. Quite a challenge, as I know how economical that engine can be. But Otsuka ‘beat it’.

A new approach to body design helped here – he allowed the aerodynamic engineers to work with clay models, ‘despite the expense’. This is unheard of in the car industry, where stylists normally hold sway. But, getting aerodynamics engineers so closely involved in the shape means the drag factor is a startling 0.25. An old Mini, by way of comparison, is 0.56….

However, while the hybrid gear is the big deal, he admits that this contributes only half to the overall 14 percent economy improvement. The other 7 percent?

This fact brings home the law of diminishing returns. And the scale of the challenge car makers face in making cars continually more green.

I have an absolute mass of information from the discussion, which I’m using to write a piece for Automotive Engineer magazine. Overall, though, meeting Otsuka-san was quite something. In a month or so’s time, we’ll be finding out if his car is as good.

… Top VW product man Ulrich Hackenberg says customers are prepared to pay more for Bluemotion ‘green’ cars. That’s because they’re 5-10mpg more economical. Win-win for VW, then. It gets more cash for each car, which customers are happy to buy in decent numbers.

With such a business model, why would it thus apply the Bluemotion changes to all models, cutting such a profitable revenue stream?

VW’s rivals may snipe and say that ‘all our cars are green, not stand-out green specials’ – but they ‘aint getting the profits of VW. That’s why Bluemotion’s here to stay.

Hackenberg also says customers are understand that they must look at engine technology, not size, to gauge performance. Good news for the downsizing trend.

… Next year, MINI will start selling patterned soft-top Convertibles. Not easy to productionise down at Oxford, but extremely lucrative, I’d have thought.

… Renault reveals the Megane Renaultsport 250’s carryover platform has been re-engineered to take a short-shift 6-speed gearbox. Why go to the trouble? Unless there are future transmission developments we’re not aware of…

… The Golf R32 will lose its heavy V6 for a more eco four-pot turbo. Probably the TTS’s 268bhp unit. It’s for handling as well as emissions, says VW.

… the origins of the TTRS’s five-pot turbo are revealed. It’s actually a tuned-up version of an engine seen in the US-spec VW Jetta. Not, as Audi claims, half a Lamborghini V10. Ahem.